define akinetes and alphanospores 

Phaeophyceae (brown algae)

Anisogamyis meant by the form of sexual reproduction by the fusion of dissimilar gametes.

Five general characteristics of algae are mentioned below:

1. Algae are either unicellular or multicellular organisms. They are free living, although some can form symbiotic relationship with other organisms.

2. They are photosynthetic organisms.

3. Algae lacks a well defined body i.e structures like root, stem, and leaves are absent.

4. They are found where there is adequate moisture.

5. Reproduction in algae occurs in both asexual and sexual forms. Asexual reproduction occurs by spore formation....

The characteristics of Charophyceae are given below:

1.it is known as green algae.

2.Plant Body is thalloid.

3.cell wall is made of cellulose and pectin.

4.mode of nutrition is photoautotrophic.

examples: Volvox, chlorella, ulva etc

Spirogyra (common names include water silk, mermaid's tresses, and blanket weed)is named as the hair of princess as its filament are silky and smooth in water.

Cephaleurous veriscence caused red rust of tea and red rust of coffee is caused by Cephaleurous arabica.